Automobile-windshield defroster



April 13, 1 965 N. LAING AUTOMOBILE-WINDSHIELD DEFROSTER Filed April '14, 1960 NIKOLAUS LAING INVENTOR.

BY JMesiem, To Madam United States Patent 3,177,794 AUTOMOBILE-WINDSHIELD DEFROSTER Nikolaus Laing, Rosenbergstrasse 24a, Stuttgart W., Germany Filed Apr. 14, 1960, Ser. No. 73,931 8 Claims. (Ci. 982) My present invention relates to electric-motor driven appliances for the generation of air jets and, more particularly, to motor-vehicle windshield defrosters.

Conventional air jet generators generally include a highspeed electric motor and an axial or radial blower driven thereby. Blowers of this type have the significant disadvantage that their rotors are of large diameter and possess, consequently, high peripheral speeds resulting in a high noise level. This noise level is a consequence of the fact that these blowers operate at relatively low Reynolds numbers and are thus capable of attaining relatively low pressure coefficients, for a given output pressure, a low pressure coefficient requires a high peripheral s eed.

A further disadvantage of these early blowers, which operate at low Reynolds numbers, is their low efficiency; hence, the motors of known air-jet generators must be proportionately more powerful. It is evident that the weight and the dimensions of the motor has a decisive influence on the compactness and, in general, the applicability of the appliances.

' It is the principal object of the present invention to produce a defroster for the windshield of an automobile .or other vehicle wherein the aforementioned disadvantages can be eliminated.

I have discovered that this object and others which will become apparent hereinafter can be attained by the use of blower rotors, closed axially at both ends and having a plurality of angularly spaced blades extending in the direction of the rotor axis with inner edges of the blades lying substantially along a first cylindrical surface centered on this axis and outer edges lying along a second cylindrical surface of a radius greater than that of the first surface and coaxial therewith. Such a blower will be defined hereinafter as a cross-flow fan or rotor. It will be understood that, in such fans, air vorticies are produced by guide elements constituting part of the housing and co-operate with the blades for inducing air flow through the rotor insuch manner that the air stream crosses the array of blades twice and is ejected tangentially from the housing. This arrangement results in a concentration of the throughput flow in a relatively narrow region of the blower so that high Reynolds numbers occur in this region with consequent high air velocities. With the automobile-windshield defroster of the present invention, a considerable increase in the blower eificiency is obtained with the result that the power consumption and Weight of the motor can be smaller and motors with low shaft power can be produced.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is an elevational View, partly in section, of an automobile-windshield defroster, according to the present invention, seen from the open side of the defroster housing which forms the air inlet;

FIG. 2 is an elevational view of this defroster and the windshield with which it co-operates; and

FIG. 3 is a perspective view of one section of the defroster of FIG. 1.

In the drawing, I show an automobile defroster, generally designated by the reference 30 in FIG. 2, which comprises a motor centrally mounted in a housing 19 between a pair of rotors l1 and 12 carried by the shaft 16 of this motor. The rotors 11 and 12 are of the cross-flow fan type described above and are provided with end disks 17 flanking the angularly spaced blades of the rotors 11 and 12 whose inner and outer edges lie along the imaginary cylindrical surfaces 31, 32 coaxial with one another and surrounding the shaft 16. The outlet means 15 of housing 19 extends the full length of the rotor blades as does the inlet opening 20 of each blower. The housing 19 forms a guide element defining the narrow gap 18 which cooperates with the rotor blades. Thus a flow of air is induced at right angles to the shaft 16 and its axis through inlet 29 and then discharged, upon traversal of the rotors, into the outlet means 15 which is constituted as guide-vane assemblies 13 provided with the deflecting vanes 14. These vanes effect a strong divergence of the stream emerging from the outlet 15 and, as indicated in FIG. 2, direct the stream toward the lateral edges of the windshield 21 so that a clear field of View 22 is provided across the major portion of the glass pane. Such an arrangement is important also for the rear window of a motor vehicle and the term windshield is to be construed as including the rear window as well. As indicated in FIGS. 1 and 2, the housing portions 13 form nozzles in a plane parallel to the axis away from the rotors to produce a sheet of air overlappingly covering the windshield; each of the rotors has essentially the same axial length as the respective housing portion.

Modifications of the invention as described and illustrated will be readily apparent to those skilled in the art and are intended to be included within the spirit and scope of the appended claims.

I claim:

1. An automobile defroster, comprising, in combination with an automobile windshield, a housing, a cross flow fan rotor journaled in said housing for rotation about an axis extending substantially parallel to said windshield, said housing forming air-inlet means for introducing air into said housing generally transversely to said axis and air-outlet means angularly offset from said air-inlet means while extending generally tangentially to said rotor and forming an elongated nozzle extending along an edge of said windshield in generally axial direction, and an electric motor connected to said rotor for driving same, said rotor having a plurality of angularly spaced blades extending in the direction of said axis with inner edges lying substantially along a first cylindrical surface centered on said axis and outer edges lying substantially along a second cylindrical surface of a radius greater than that of said first cylindrical surface and coaxial therewith whereby air drawn into said housing through said inlet means passes through said rotor and is ejected tangentially through said outlet means, said inlet and outlet means constituting openings in said housing extending substantially over the entire length of said blades.

2. An automobile defroster, comprising, in combina tion with an automobile Windshield, a housing, a crossflow fan rotor journaled in said housing for rotation about an axis extending substantially parallel to said windshield, said housing forming air-inlet means for introducing air into said housing generally transversely to said axis and air-outlet means angularly offset from said air-inlet means while extending generally tangentially to said rotor and forming an elongated nozzle extending along an edge of said windshield in generally axial direction, said outlet means being flared outwardly from said rotor in the direction of said nozzle, and an electric motor connected to said rotor for driving same, said rotor having a plurality of angularly spaced blades extending in the direction of said axis with inner edges lying substantially along a first cylindrical surface centered on said axis and outer edges lying substantially along a second cylindrical surface of a radius greater than that of said 3 first cylindrical surface and coaxial therewith whereby air drawn into said housingthrough said inlet means passes through said rotor and is ejected tangentially through said outlet means, said inlet and outlet means constituting openings in said housing extending substantially over the entire length of said blades.

3. An automobile defroster, comprising, in combination with an automobile windshield, a housing, acrossfiow fan rotor journaled in said housing for rotation about an axis extending substantially parallel to said Windshield, said housing forming air-inlet means for introducing air into said housing generally transversely to said axis and air-outlet means angularly offset from said air-inlet means while extending generally tangentially to said rotor and forming an elongated nozzle extending along an edge of said windshield in generally axial direction, guide means in said outlet means extending generally transversely to said axis for distributing the air stream ejected from said nozzle toward the lateral edges of said windshield, and

an electric motor connected to said rotor for driving same, said rotor having a plurality of angularly spaced blades extending in the direction of said axis with inner edges lying substantially along a first cylindrical surface centered on said axisand outer edges lying substantially along a second cylindrical surface of a radius greater than that of said first cylindrical surface and coaxial therewith whereby air drawn into said housing through said inlet means passes through said rotor and is ejected trangentially through said outlet means, said inlet and outlet means constituting openings in said housing extending substantially over the entire length of said blades.

4. An automobile defroster, comprising, in combination with an automobile windshield, a housing,a pair of axially spaced cross-flow fan rotors journaled in'said housing for rotation about a common axis extending substantially parallel to said windshield, said housing forming air-inlet means for introducing air into said housing generally transversely to said axis and air-outlet means angularly offset from said air-inlet means while extending generally tangentially. to said rotor,-said air-outlet means forming an elongated nozzle along an edge of said windshield in generally axial direction; guide means in said outlet means extending generally transversely to said axis for distributing the air stream ejected from said nozzle toward the lateral edges of said windshield; and an electric motor coupled with said rotors at an axial location therebetween for driving same, each of said rotors having a plurality of angularly spaced blades extending in the direction of said axis with inner edges lying substantially along a first cylindrical surface centered on said axis and outer edges lying substantially along a second cylindrical surface of a radius greater than that of said first cylindrical surface and coaxial therewith whereby air drawn into said housing through said inlet means passes through said rotor and is ejected tangentially through said outlet means.

5. An automobile defroster, comprising, in combination with an automobile windshield, a housing, a pair of axially spaced cross-flow fan rotors journaled in said housing for rotation about a common axis extending substantially parallel to said windshield, said housing forming air-inlet means for introducing air into said housing generally transversely to said axis and air-outlet means angularly offset from said air-inlet means while extending generally tangentially to said rotors, said air-outlet means forming a respective elongated nozzle assigned to each of said rotors along an edge of said Windshield in generally axial direction; guide means in said outlet means extending generally transversely to said axis for distributing the air stream ejected from said nozzles divergingly toward the lateral edges of said windshield; and an electric motor coupled with said rotors at an axial location therebetween for driving same, each of said rotors having a plurality of angularly spaced blades extending in the direction of said axis with inner edges lying substantially along a first cylindrical surface centered on said axis and outer edges lying substantially along a second cylindrical surface of a radius greater than that of said first cylindrical surface and coaxial therewith whereby air drawn into said housing through said inlet means passes through said rotor and is ejected tangentially through saidoutlet means.

6. A defroster as defined in claim 5 wherein said rotors have a common shaft, said motor being mounted upon said shaft for rotating same.

7. A defroster as defined in claim 6 wherein said housing is subdivided into two housing portions each surrounding a respective one of said rotors and provided with the respective nozzle, said nozzles diverging in a plane parallel to said axis away from said rotors to produce a sheet of air overlappingly covering said windshield.

8. A'defroster as defined in claim 7 wherein each of said rotors has essentially the same axial length as the respective housing portion.

References Cited in the file of this patent UNITED STATES PATENTS 507,445 Mortier Oct. 24, 1893 1,429,130 Dutton Sept. 12, 1922 1,823,579 Anderson Sept. 15, 1931 1,920,952 Anderson Aug. 8, 1933 1,950,768 Anderson Mar. 13, 1934 1,978,413 Child Oct. 30, 1934 1,998,670 Goshorn et a1 Apr. 23, 1935 2,263,723 Findley Nov. 25, 1941 2,876,369 Doerner Mar. 3, 1959 2,894,728 Davis July 14, 1959 2,942,773 Eck June 28, 1960 2,968,436 Coester Jan. 17, 1961 3,035,760 Simmons May 22, 1962 FOREIGN PATENTS 174,821 Austria .a May 11, 1953 

1. AN AUTOMOBILE DEFROSTER, COMPRISING, IN COMBINATION WITH AN AUTOMOBILE WINDSHIELD, A HOUSING, A CROSS FLOW FAN ROTOR JOURNALED IN SAID HOUSING FOR ROTATION ABOUT AN AXIS EXTENDING SUBSTANTIALLY PARALLEL TO SAID WINDSHIELD, SAID HOUSING FORMING AIR-INLET MEANS FOR INTRODUCING AIR INTO SAID HOUSING GENERALLY TRANSVERSELY TO SAID AXIS AND AIR-OUTLET MEANS ANGULARLY OFFSET FROM SAID AIR-INLET MEANS WHILE EXTENDING GENERALLY TANGENTIALLY TO SAID ROTOR AND FORMING AN ELONGATED NOZZLE EXTENDING ALONG AN EDGE OF SAID WINDSHIELD IN GENERALLY AXIAL DIRECTION, AND AN ELECTRIC MOTOR CONNECTED TO SAID ROTOR FOR DRIVING SAME, SAID ROTOR HAVING A PLURALITY OF ANGULARLY SPACED BLADES EXTENDING IN THE DIRECTION OF SAID AXIS WITH INNER EDGES LYING SUBSTANTIALLY ALONG A FIRST CYLINDRICAL SURFACE CENTERED ON SAID AXIS AND OUTER EDGES LYING SUBSTANTIALLY ALONG A SECOND CYLINDRICAL SURFACE OF A RADIUS GREATER THAN THAT OF SAID FIRST CYLINDRICAL SURFACE AND COAXIAL THEREWITH WHEREBY AIR DRAWN INTO SAID HOUSING THROUGH SAID INLET MEANS PASSES THROUGH SAID ROTOR AND IS EJECTED TANGENTIALLY THROUGH SAID OUTLET MEANS, SAID INLET AND OUTLET MEANS CONSTITUTING OPENINGS IN SAID HOUSING EXTENDING SUBSTANTIALLY OVER THE ENTIRE LENGTH OF SAID BLADES. 